Effect of daily environmental temperature on farrowing rate and total born in dam line sows
Effect of daily environmental temperature on farrowing rate and total born in dam line sows
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DOI：
10.2527/jas.2012-5902
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发表时间：
2013-06-01
影响因子：
3.3
通讯作者：
van der Waaij, E. H.
中科院分区：
文献类型：
--
作者：
Bloemhof, S.;Mathur, P. K.;van der Waaij, E. H.
已知热应激对母猪的繁殖性能有不利影响。然而，重要的是要知道在繁殖周期中的哪一天或哪一段时间热应激对设计适当的遗传或管理策略的影响最大。因此，本研究采用5种不同的热应激指标，确定对母猪产仔率和总产仔数影响最大的天数和时期。数据包括来自西班牙和葡萄牙16个农场的5024头荷兰约克郡母猪的22,750条记录。在一个给定的一天的热应力测量的最高温度，昼夜温差和热负荷。考虑到不同的上临界温度，使用3种定义来估计热负荷。在繁殖周期中具有最大影响的天数的确定是基于热应激变量和繁殖性状之间的皮尔逊相关性，估计在繁殖周期中的每一天。拟合多项式函数来描述这些相关性的趋势，具有最大负相关性的天数被认为是具有最大效应的天数。最高温度的相关性最大，其次是热负荷和昼夜温差。后备母猪的分娩率和总出生率的相关性比母猪更强。这意味着热应激对后备母猪的繁殖性能的影响比对母猪的影响更大。第一次授精前第三周（21~14 d）的热应激对产仔率的影响最大。热应激对总产仔数影响最大的时期为授精前7 d至授精后12 d。在这些期间，连续几天的温度之间的相关性非常高（> 0.9）。因此，以第一次输精前21 d的最高温度作为产仔率的预测指标，以输精成功日的最高温度作为总产仔数的预测指标，可以作为商品母猪场热应激的预测指标。此外，子组之间的差异，公畜被确定在应对高温。这可能表明耐热性的遗传选择的可能性。
Heat stress is known to adversely affect reproductive performance of sows. However, it is important to know on which days or periods during the reproduction cycle heat stress has the greatest effects for designing appropriate genetic or management strategies. Therefore, this study was conducted to identify days and periods that have greatest effects on farrowing rate and total born of sows using 5 different measures of heat stress. The data consisted of 22,750 records on 5024 Dutch Yorkshire dam line sows from 16 farms in Spain and Portugal. Heat stress on a given day was measured in terms of maximum temperature, diurnal temperature range and heat load. The heat load was estimated using 3 definitions considering different upper critical temperatures. Identification of days during the reproduction cycle that had maximum effect was based on the Pearson correlation between the heat stress variable and the reproduction trait, estimated for each day during the reproduction cycle. Polynomial functions were fitted to describe the trends of these correlations and the days with greatest negative correlation were considered as days with maximum effect. Correlations were greatest for maximum temperature, followed by those for heat load and diurnal temperature range. Correlations for both farrowing rate and total born were stronger in gilts than in sows. This implies that heat stress has a stronger effect on reproductive performance of gilts than of sows. Heat stress during the third week (21 to 14 d) before first insemination had largest effect on farrowing rate. Heat stress during the period between 7 d before successful insemination until 12 d after that had largest effect on total born. Correlations between temperatures on consecutive days during these periods were extremely high (>0.9). Therefore, for farrowing rate the maximum temperature on 21 d before first insemination and for total born the maximum temperature at day of successful insemination can be used as predictive measures of heat stress in commercial sow farms. Additionally, differences between daughter groups of sires were identified in response to high temperatures. This might indicate possibilities for genetic selection on heat tolerance.